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Oracle Concepts by Burleson
Consulting |
PL/SQL Self Study Questions
1. What are some of the advantages of
using PL/SQL over traditional procedural languages?
Answer: In
traditional languages such as COBOL, Fortran, or C++, the SQL
statements must be embedded inside the program and the program can be
run through special pre-compiler to detect the SQL statements and
replace them with native calls to the Oracle database management
system. PL/SQL is superior to native programming languages in
the respect that didn’t the Oracle database access is somewhat
transparent. PL/SQL also has the advantage of being able to be
called independently from client side applications.
2. What is the concept of Row-oriented
processing, and why is it important for relational database access?
Answer: SQL is not
a row-oriented language. The result set from an SQL statement
could be a single row or 10,000 rows. Hence, native SQL is not
appropriate type of language when we need to interrogate individual
rows within a set. The relational model offers us the ability to
declare and use cursors in order to extract or results set, and
interrogate data, one row at a time.
3. What is the basic
difference between a stored procedure and a function within Oracle?
Answer: Functions
and stored procedures are identical in terms of the type of code that
can be placed within them, but functions have a restriction that they
must always return a value to the calling program.
4. What are the three types
of looping constructs within PL/SQL?
Answer: Oracle’s
PL/SQL provides three types of loop structures. We have the
standard for loop structure, which allows looping for specific
number of iterations, the repeat until looping construct, and
the while loop construct. These three types of looping
constructs are very similar to those in traditional procedural
languages such as Visual Basic and C++.
5. Why does Feuerstein make
such a big deal about modularity in chapter 15 of your readings?
Answer: the
benefits of modular programming are very well known within the IT
community. Modularity allows code re-use, provides a mechanism
for the elimination of code redundancy, and also makes procedural code
easier to read and understand.
6. Why is it important to
place stored procedures and functions within packages?
Answer: When stored
procedures and functions are encapsulated into a package, the package
can be cached inside the Oracle SGA thereby making it ineligible for
paging and fully resident in the RAM. This will make all of the
procedures run far faster than stored procedures and functions that
are not pinned inside the Oracle SGA.
For more details,
see the "Easy
Oracle Series" a set of books especially designed by Oracle
experts to get you started fast with Oracle database technology.
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